Liners for comminution apparatus

ABSTRACT

Comminution apparatus such as ball mills, pebble mills, vibration mills and the like are lined with a hollow, inflatable, resilient body made of a suitable elastomer such as rubber. The body is inflated hydraulically or pneumatically. In a typical case the cylinder of a mill is lined with a hollow tube formed as a helix.

United States Patent 1191 111] 3,920,191

Bradley 5] Nov. 18, 1975 LINERS FOR COMMINUTION APPARATUS 2,589,603 3/1952 Cohen 241/1310. 30 2,711,557 6/1955 Russell 241/182 [75] Inventor- Albert Bradley f 3,191,874 6/1965 Drinkwater et a1. 241/183 Johannesburg South Afnca 3,670,970 6/1972 Szegvari 241/182 x [73] Assignee: Trelleborgs Gummifabrik Aktiebolag, Trelleborg, Sweden Primary Examiner Roy Lake 22 Filed; 2 7 Assistant Examiner-E. F. Desmond Attorney, Agent, or FirmBrowne, Beverldge, [211 APPl- NW 441,788 DeGrandi & Kline [30] Foreign Application Priority Data Feb. 15, 1973 South Africa 73/1076 [57] ABSTRACT Comminution apparatus such as ball mills, pebble 241/182 :64??? 62 mills, vibration mills and the like are lined with a hol- [58] Fi d 182 183 low, inflatable, resilient body made of a suitable elase 0 are tomer such as rubber. The body is inflated hydraulically or pneumatically. In a typical case the cylinder of [56] SE ZE S E a mill is lined with a hollow tube formed as a helix. 2,582,872 l/1952, Krengel 24l/DIG. 30 I 2 Claims, 2 Drawing Figures U.S. Patent Nov. 18, 1975 LINERS FOR COMMINUTION APPARATUS This invention relates to liners for comminution apparatus such as ball mills, pebble mills, vibration mills and the like.

These mills have one thing in common: a charge is constantly agitated in a cavity. As a result of the movement of the charge the walls of the cavity become worn. It is therefore customary to line the cavity with wear pieces of various kinds. Typically they may be made of steel, alloys or elastomers such as rubber.

It has been found that when elastomers are employed, the material must be of significant thickness if the rate of wear is not to be excessive. The applicant believes that this is so because damage to the elastomer by abrasion and impact is reduced by increasing the compliance of each wear piece.

An object of the invention is to provide wear pieces for apparatus of the kind set out above which can have a reduced rate of wear compared to prior art wear pieces made of elastomers.

According to the invention a method of providing a wearpiece for a comminution apparatus includes the steps of lining the apparatus with a hoHow, inflatable, resilient body and inflating the body.

Further according to the invention a wear piece for a comminution apparatus comprises a hollow inflatable, resilient body made of a suitable elastomer such as rubbet.

The wear piece of the invention may be inflated pneumatically or hydraulically. If required, the wear piece may be fitted with an inner tube analogous to that used in vehicle tyres.

The wear piece may take a variety of shapes and may be provided with treads shaped to prevent slip between charge and wear-piece or to provide lifter bars.

In one form of the invention a wear piece is formed as a continuous tube which is helically wound inside a cylindrical cavity. In another form a cylindrical cavity is lined with a series of contiguous annular bodies. In yet another form the wear pieces are in the shape of axial bars lining the cavity.

The invention is further discussed with reference to the accompanying drawings, in which FIG. 1 is a fragmentary perspective view of a mill wall, and

FIG. 2 is a similar view of another embodiment.

FIG. 1 shows a mill having a shell 3 and a continuous tube 4 made of a suitable elastomer. The tube 4 is rolled up inside the mill tube so as to form a helix extending from end to end of the tube.

The surface of the tube 4 facing the interior of the shell is provided with a suitable tread to prevent slip between the charge and the tube 4. A valve (not shown) passes to the tube 4 through the shell 3 at a suitable position. The tube is inflated through the tube 4, and inflation pressure causes the tube 4 to be held in place very firmly.

FIG. 2 illustrates a case where several axial tubes 5 line the shell 3. The tubes 5 are moulded or attached together to form a raft. Each raft is bolted to the shell 3 at suitable positions (not shown). Several rafts form a continuous circumferential liner. Once more treads are moulded on the surface facing the interior of the shell of each tube. Lifter bars may be moulded on some of the tubes, alternately, some tubes may project radially inward more than others'to form lifter bars. Valves (not shown) pass through the shell 3 to allow for inflation from outside. For convenience they may all be connected to a common manifold.

The tubes 4 or 5 may be inflated by compressed air, or by means of a suitable hydraulic fluid. In either case the compliance of the liner is increased advantageously so that the rate of wear is also reduced for the same tread thickness. A further advantage is that the weight of the mill is reduced as well as the noise generated during operation of the mill.

Note that the end of a given mill may be lined with end pieces also composed of inflatable members, e.g. wound in a spiral or forming concentric rings or parallel strips.

I claim:

1. In a comminution mill having means providing a cavity for containing a charge and means for agitating the charge in the cavity,

a resilient elastomer wear piece lining the cavity and exposed directly to the charge within the cavity, said wear piece having treads formed in its exposed surfaces to prevent slippage between a charge and the liner, said wear piece being hollow and inflated to reduce its rate of wear produced by abrasion and impact of the charge thereagainst.

2. In a comminution mill having means providing a cavity for containing a charge and means for agitating the charge in the cavity,

a resilient elastomer wear piece lining the cavity and exposed directly to the charge within the cavity, said wear piece being continuous and arranged helically within the cavity, said wear piece being hollow and inflated to reduce its rate of wear produced by abrasion and impact of the charge thereagainst. 

1. In a comminution mill having means providing a cavity for containing a charge and means for agitating the charge in the cavity, a resilient elastomer wear piece lining the cavity and exposed directly to the charge within the cavity, said wear piece having treads formed in its exposed surfaces to prevent slippage between a charge and the liner, said wear piece being hollow and inflated to reduce its rate of wear produced by abrasion and impact of the charge thereagainst.
 2. In a comminution mill having means providing a cavity for containing a charge and means for agitating the charge in the cavity, a resilient elastomer wear piece lining the cavity and exposed directly to the charge within the cavity, said wear piece being continuous and arranged helically within the cavity, said wear piece being hollow and inflated to reduce its rate of wear produced by abrasion and impact of the charge thereagainst. 